Eventhough MC preamps can be excellent in RIAA accuracy, most MC cartridges spoil the fun wrt to their dB accuracy (0.2-0.5dB RIAA versus a sloped MC curve often starting at 3...6dB at 20Hz and making a dive after that to 0dB or worse and followed by a peak again)

Not as bad as it seems but still enough to wonder if there are MC preamps that have extra selections to compensate for the cartridge curve (besides the loading of course)

I don't mean the different RIAA curves but real options to compensate for the MC cartridge "flaws"

As an illustration I add the Benz Micro Curve that also sounds as it looks....so no myth here. Regardless of any setting/adjustment/phono-pre, the curve stays like this. With my new LCR tube phono having a couple of dB reduction at 10-20Hz, the low part of the curve gets flatter. I added a switchable "shelving" from 1kHz to 20kHz that lifts approx 4dB at 20 kHz. Not a perfect curve but sounding good again.

Expected a horizontal line...but I think I had this before measuring in the FFT mode. RTA with max hold gave the horizontal line.
So, this curve seems to be perfect if it is not a real slope-down....right?

Pink noise is 3dB/octave slope, so this indicates that its as expected.

Test records get confusing very quickly in this aspect and a number are not as accurate as we might like! And some are RIAA, some are constant velocity and some are a mix. This is about the best pink noise record I have seen.

Do you have the raw file from adjust+ you can supply me. Then we can get that compared with the same file done on the LPS I showed the FR for above. Hopefully we can cal out the record and get to your actual FR plot.